Existing black zirconia ceramics are obtained by two processing methods. One method includes forming a green body from white zirconia and then performing carburization. This process for preparing a black zirconia sintered body involves complicated techniques, needs sintering under a protective atmosphere, and has high requirements for equipment. Additionally, the pigment has high volatility during the sintering process, and the equipment is seriously polluted. The other method includes adding a metal oxide coloring agent to zirconia powder. However, due to the problems such as a tendency to form large particles and an uneven distribution of the metal oxide, the sintered body of zirconia ceramic has low strength, cracking, uneven and dark color, etc.
CN1566021 discloses a method for preparing black zirconia ceramics, in which the work piece blank needs to be sintered under vacuum or protective atmosphere after being dewaxed and degreased, and which has high requirements for sintering equipment and high sintering temperature (1550 to 1650° C.). This method involves complicated manufacturing techniques, and requires use of graphite for carburizing and coloring treatment during the sintering process, and the sintering process also leads to serious pollution of the equipment.